1. Field of the Invention
The present invention relates to a color image display device, a color filter substrate, a color pixel array substrate, and an electronic device and, more specifically to, a color image display device, a color filter substrate, a color pixel array substrate, an image display device, and an electronic device by which an outer edge of an image display region have a non-rectangular shape in part or as a whole.
2. Description of the Related Art
An image display device is used often in the case of outputting various kinds of display information in an image such as characters or illustrations in a condition where it is mounted not only on a single apparatus but also on a variety of apparatuses. In particular, a thin-type image display device such as a recently prevailing liquid crystal display (LCD) is mounted on a mobile terminal apparatus such as a cellular phone because of its feature of being lightweight also. In the type of image display device, desirably its display region is shaped not only into a rectangle with four right-angled corners but also into a non-rectangle such as a circle or an ellipsoid (see, for example, Patent Document 1 (Japanese Patent Application Laid Open Publication No. Hei04-177986); Patent Document 2 (WO93/04460); and Patent Document 3 (Japanese Patent Application Laid Open Publication No. 2006-276359)).
As this type of image display devices, one such is known that it is mounted, for example, on the right surface side of a cellular phone and the image display region of this device is made circular in shape so that outsides of the outer edge of this region may be covered over with a circularly-opened frame member.
It is here assumed that in order to provide color display on a screen of this device, each unit pixel of its image display region includes a sub-pixel which turns red (R), that which turns green (G), and that which turns blue (B) respectively of the three primary colors. To make the image display region circular, it is covered with a light-shielding layer 180 that nearly matches its outer edge (region border line) 160a as shown in FIG. 20. By doing so, in an inner unit pixel 20 in this region, the R-, G-, and B-inner sub-pixels 20r, 20g, and 20b of this unit pixel are all exposed so that color balance may be maintained. In contrast to it, in an end portion unit pixel 101 along the outer edge 160a, any one of R-, G-, and B-end portion sub-pixels 101r, 101g, and 101b may be covered with the light-shielding layer 180 to resultantly produce a difference in exposure area between them; this difference disturbs the color balance, giving rise to so-called coloring. It is to be noted that in the figure the characters of “R”, “G”, and “B” indicated on the respective sub-pixels are not really displayed on their surfaces but just are given for facilitating understanding (which holds true also in the drawings described hereinafter).
Accordingly, to maintain the color balance, Patent Document 4 (Japanese Patent Application Laid Open Publication No. 2006-276580) proposes reducing differences in light development area among the end portion sub-pixels by changing the width of a black matrix which shields from light the light development regions of the R-, G-, and B-end portion sub-pixels making up the end portion unit pixel and the width itself of each of those end portion sub-pixels.
Further, to suppress coloring, Patent Document 5 (Japanese Patent Application Laid Open Publication No. 2005-315960) proposes reducing the relative differences in area among the end portion sub-pixels by improving the degree of display fineness by decreasing the area of each of the R-, G-, and B-end portion sub-pixels making up the end portion unit pixel.
However, in the case of the related technologies described in Patent Document 4, if the end portion sub-pixels 101r of the end portion unit pixel 101 is mostly covered over with the light-shielding layer 180 as shown in FIG. 21, it is difficult to maintain the color balance only by adjustment of the black matrix width etc.
Further, the related technologies described in Patent Document 5 cannot accommodate a case where the R-, G-, and B-end portion sub-pixels making up the end portion unit pixel are covered over with the light-shielding layer in an indefinite shape, because those technologies intend only to reduce the areas of those end portion sub-pixels in order to suppress coloring at the end portions in the rectangular-shaped image display region. That is, similar to the related technologies described in Patent Document 4, even those described in Patent Document 5 may find it difficult to maintain color balance if there occurs a difference in area ratio among the end portion sub-pixels. Further, various circuit components which operate the end portion unit pixels cannot be arranged in much the same way as the inner unit pixels and so need to be set up in a small region corresponding to the end portion sub-pixels. Accordingly, the LCD, for example, may find it difficult in some cases to dispose in a small region a variety of components such as a switching active element, a storage capacitor, and a transparent pixel electrode that make up each pixel circuit.